Dominant theory says that desertification is caused by overgrazing.

My toughest work this year has been serving on the jury of this year’s Buckminster Fuller Challenge. Our work has been tough because we’ve had to assess high quality entries that range from the use of social media to organize urban food systems to transforming Chicago into a giant water treatment machine; from helping Indian women solar electrify their own villages to the use of cattle to reverse the spread of deserts around the world.

But the experience has also been uplifting. As a jury, we were instructed to look for a “bold, visionary, but tangible initiative that addresses a well-defined need of critical importance” — and we have been spoiled for choice. Our winner, who was announced yesterday at the National Press Club in Washington DC, has received a $100,000 prize to support the development and implementation of their work. I couldn’t be there myself, so my contribution is write about some of the finalists over the coming days and weeks, starting with the recipient of the 2010 Grand Prize: Operation Hope.

A quarter of the land area of Earth is turning into desert. Three quarters of the planet’s savannas and grasslands are degrading. And because the main activity on rangelands is grazing livestock, on which 70 percent of the world’s poorest people depend, grassland deterioration therefore causes widespread poverty.

Desertification affects climate change, too. According to Richard Douthwaite, who leads the Carbon Cycles and Sinks Network, agriculture and land-use emissions are 27 percent of the global total of harmful emissions. (Douthwaite’s network is developing policies that will enable the Irish land mass to become a carbon sink rather than a source of greenhouse emissions. His organization, the Foundation for the Economics of Sustainability, Feasta, was instrumental in the invitation to Allan Savory to give a lecture at Trinity College, Dublin which may bee seen online here.)

Enormous research efforts have been made to understand and reverse desertification, but until recently, and with one remarkable exception, to no avail. That exception, Operation Hope, has transformed 6,500 acres of of parched and degraded grasslands in Zimbabwe into lush pastures replete with ponds and flowing streams – even during periods of drought.

Surprisingly, this was accomplished through a dramatic increase in the number of herd animals on the land. Behind Operation Hope is an approach called “holistic management,” which they apply to rangeland practice. Developed over the past 50 years by Operation Hope founder Allan Savory, a former wildlife biologist, farmer, and politician, it challenges the dominant theory that desertification is caused by overgrazing.

Savory’s approach is based on a singular insight: grasses can’t graze themselves. Before man came along, herbivores co-evolved with perennial grasses. “When a large herd moved around freely — accompanied, that is, only by pack-hunting predators – they dunged and urinated with very high concentration on the grass,” he says. “No animals like to feed on their own feces, so they had to move off of their own feces within 1-3 days and they could not return until the dung had weathered and was clean again.”

Moving across the land in large herds, the herbivores trample and compact soils in much the way that a gardener does to encourage plant growth — while also fertilizing the soil with concentrated levels of nutrient-rich animal wastes. This approach aligns itself with nature a comprehensive way; it increases plant growth, improves rural livelihoods through additional livestock, and increases wildlife populations across the landscape.

Grasses depended on herbivores to help them with their decay process. When large herbivores such as Kudu and Cape Buffalo, disappear, grasses begin to decay far more slowly through oxidation. When millions of tons of vegetation are left standing, dying upright, the result is to block light from reaching growth buds; the next year, the entire plant dies. The death of grass leads to bare ground, and desert spreads.